解读ResultSet的遍历方法

String sql = "select * from student";
ResultSet rs = stmt.executeQuery(sql);

while(rs.next()){
        int id = rs.getInt(1);
        String name = rs.getString(2);
        String gender = rs.getString(3);
        System.out.println("id:"+id+" 姓名："+name+" 性别："+gender);
    }

while(rs.next()){
        int id = rs.getInt("id");
        String name = rs.getString("name");
        String gender = rs.getString("gender");
        System.out.println("id:"+id+" 姓名："+name+" 性别："+gender);
    }

BeanHandler<Student> bh =new BeanHandler<Student>(Student.class);
//rs是ResultSet得到的从返回集合 
Student li = bh.handle(rs);

while (rs.next()){ 
    String id=rs.getString(1);    
    String name=rs.getString(2);    
    int age=rs.getInt(3);    
    String sex=rs.getString(4);    
    System.out.println(id +"--"+ name+"--"+age+"--"+sex);}

package cn.cast.jdbc;

import java.sql.*;

public class JdbcDemo4 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
     //注册驱动
     Class.forName("com.mysql.cj.jdbc.Driver");
     //获取数据库连接对象
      Connection conn= DriverManager.getConnection("jdbc:mysql:///stu?serverTimezone=GMT","root","root");
      //定义sql语句
        String sql="select * from ss";
        //获取执行sql的对象
        Statement stmt=conn.createStatement();
        //执行sql
        ResultSet rs=stmt.executeQuery(sql);
        //处理结果(以next返回值判断是否在最后一行，然后获取数据）
        while (rs.next()){
            String id=rs.getString(1);
            String name=rs.getString(2);
            int age=rs.getInt(3);
            String sex=rs.getString(4);
            System.out.println(id +"--"+ name+"--"+age+"--"+sex);
        }
        //释放资源
        rs.close();
        stmt.close();
        conn.close();

    }
}